Various types of input devices such as a pointing device allow a user to manipulate a cursor of a computer. A common type of pointing device is a mouse that is typically used for desktop computers or docked laptop computers. A mouse allows for cursor manipulation on a visual display screen of a personal computer or workstation, for example. Cursor manipulation includes actions such as rapid relocation of a cursor from one area of the display screen to another area, pointing to an object, highlighting an object, selecting an object, moving or dragging an object, and so forth.
A mouse typically includes various mechanical parts. In a “roller ball” mouse, for example, a user controls the cursor by moving the mouse over a surface, such as a mouse pad, so that the cursor moves on the display screen in a direction and a distance that is proportional to the movement of the mouse. Similarly, a “track ball” mouse may include a stationary ball with freedom of movement that is rolled by a user with a finger or thumb to control cursor movement on the display screen. Both the roller ball and track ball mice, however, have drawbacks associated with any device that have mechanical parts. Namely, over time the mechanical components wear out, become dirty, or simply break down so that the cursor can no longer be accurately manipulated.
Recently, “optical” mice that use image sensors have been developed. An optical mouse may produce a collimated beam of light that illuminates a surface upon which the mouse rests. A sensor array portion of an image sensor receives the reflected images of the surface as the mouse is traversed across a surface. The changes in successive reflected images are then determined to be mouse movement, which is then interpreted as a desired cursor movement. Such designs are typically superior to mechanical designs.
Despite such improvements in tracking movement of a mouse, there are several ergonomic issues for a mouse that remain to be solved. A mouse may have various design features, to include shape, size, button positions, grip positions, pointing performance, and so forth. A particular combination of design features may affect user comfort, fatigue, pointing accuracy, usability, and so forth. In some cases, a poor design may even lead to health issues such as wrist injuries. Consequently, there is a need for improvements in mouse design to increase comfort, performance and desirability of a mouse, while maintaining the efficiencies gained by improved movement tracking techniques.